Die castable centrifugal fan

ABSTRACT

Disclosed herein is a fan assembly comprising a first fan member including a plurality of angularly spaced vane portions extending perpendicularly of the axis of intended fan rotation and perpendicularly to a plane perpendicular to the axis of intended fan rotation and having axially outer edges, a second fan member including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first member, each of the second member vane portions having an axially inner edge and an axially outer part extending arcuately in a plane extending parallel to the intended axis of fan rotation and perpendicularly to a plane extending radially from and containing the intended axis of fan rotation, and separable interfitting means on the first and second fan members for aligning the outer edges of the vane portions of the first fan member with the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

United States Patent 1191 Hackbarth et a1.

[ 1 Jan. 1,1974

[ DIE CASTABLE CENTRIFUGAL FAN [73] Assignee: Outboard Marine Corporation,

Waukegan, 111.

[22] Filed: Jan. 2, 1973 [21] Appl. No.: 320,073

[52] U.S. Cl 415/213, 416/183, 416/186, 415/D1G. 5 [51] Int. Cl. F04d 17/08, F04d 29/28 [58] Field of Search 416/183, 186; 415/143, 213

[56] References Cited UNITED STATES PATENTS 1,427,391 8/1922 Johns 416/183 1,919,970 7/1933 Woods 416/183 1,959,703 5/1934 Birmann 1 416/183 2,366,251 1/1945 Fulleman 416/186 2,438,867 3/1948 Rockwell et al. 416/183 2,469,125 5/1949 Meisser... 416/183 2,652,191 9/1953 Buchi 416/186 2,482,462 9/1949 Browne 415/186 3,285,187 11/1966 Anderson 416/183 FORElGN PATENTS OR APPLICATIONS 462,853 7/1928 Germany 416/183 755,192 11 1952 Germany .l 416/186 838,192 5/1952 Germany 416/183 482,965 7 1953 ltaly 416/186 Primary Examiner-Henry F. Raduazo AttorneyRobert E. Clemency et a1.

[57] ABSTRACT Disclosed herein is a fan assembly comprising a first fan member including a plurality of angularly spaced vane portions extending perpendicularly of the axis of intended fan rotation and perpendicularly to a plane perpendicular to the axis of intended fan rotation and having axially outer edges, a second fan member including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first member, each of the second member vane portions having an axially inner edge and an axially outer part extending arculately in a plane extending parallel to the intended axis of fan rotation and perpendicularly to a plane extending radially from and containing the intended axis of fan rotation, and separable interfitting means on the first and second fan members for aligning the outer edges of the vane portions of the first fan member with the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

4 Claims, 11 Drawing; Figures DIE CASTABLE CENTRIFUGAL FAN BACKGROUND OF THE INVENTION The invention relates generally to internal combustion engines and more particularly to fan structures for air cooling internal combustion engines. Centrifugal type cooling fans have been provided in the past for delivering cooling air through a shroud and past the engine block of an internal combustion engine. Such fans have sometimes included vanes with swirl portions which provide for increased fan efficiency. However, due to the vane shape which affords the swirl construction, such fans were expensive to manufacture and were not capable of being die cast.

SUMMARY OF THE INVENTION The invention provides a method of die casting a centrifugal fan having a plurality of vanes including a swirl configuration. In addition, the invention provides a fan assembly comprising a first fan member receivable on a rotary member and including a plurality of angularly spaced vane portions extending radially outwardly of the axis of rotation and perpendicular to a plane perpendicular to the axis of rotation and having axially outer edges, together with a second fan member received on the rotary member outwardly of the first fan member and including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first fan member. Each of the second member vane portions has an axially inner edge and an outer part extending arcuately in a plane extending parallel to the rotary axis and perpendicular to a plane extending radially from and containing the rotary axis. In addition, separable interfitting means are provided on the first and second fan members for aligning the outer edges of the vane portions of the first fan member and the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

In further accordance with the invention, the interfitting means comprises a circumferential flange extending radially outwardly from the radially outer ends of the vane portions of the second fan member, which flange has a surface with a plurality of radially extending recesses therein, said recesses receiving the radially and axially outer parts of the first member vane portions.

In accordance with the invention, the method involves die casting the first fan member with a parting line located along a flange surface from which the vane portions extend. The method also involves die casting the second fan member with a parting line extending along the axially outer radially extending margins of the outer or swirling part of the vane portions. After die casting, the fan members are assembled in coaxial alignment and with the vane portions of the first and second members in alignment. Each of the fan members includes appropriate draft extending from the appropriate parting line.

One of the principal objects of the invention is the provision of a method of manufacturing a centrifugal fan which includes vanes having swirling portions and which is formed from die cast members.

Another of the principal objects of the invention is the formation of a centrifugal fan with swirling vanes, which fan can be die cast in two cooperating members each having appropriate drafts from an applicable parting line.

Another of the principal objects of the invention is the provision of an internal combustion engine including a fan assembly comprising inner and outer fan members, together with interfitting means for separably assembling the fan members on a crankshaft or other shaft in aligned relation and for rotatably driving the assembly from such shaft.

Another of the principal objects of the invention is the provision of a centrifugal fan including first and second die cast members, each of the members having separable interfitting parts affording proper alignment of the fan members.

Other objects and advantages of the invention will become known by reference to the following specifications, claims and drawings.

DRAWINGS FIG. 1 is a fragmentary view, partially in section, of an internal combustion engine including a fan assembly embodying various of the features of the invention.

FIG. 2 is an axially outer view of the inner fan member incorporated in the fan assembly shown in FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is an enlarged view of the outer portion of the outer part of one of the vane portions of the fan member shown in FIG. 2.

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4.

FIG. 6 is a sectional view taken along line 66 of FIG. 2.

FIG. 7 is an axially outer view of the outer fan member included in the fan assembly shown in FIG. 1.

FIG. 8 is a sectional view taken along line 8--8 of FIG. 7.

FIG. 9 is a sectional view taken along line 9-9 of FIG. 7.

FIG. 10 is an axially inner view of the outer fan member incorporated in the fan assembly shown in FIG. 1.

FIG. 11 is a sectional view taken along line -11 of FIG. 10.

Before explaining the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts set forth in the following general description or illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

General Description of the Invention Fragmentarily shown in the drawings is an internal combustion engine 11 including a crankcase or engine block which journals a crankshaft 15 having a portion 17 extending exteriorly of the engine block 13.Received on the extending crankshaft portion 17 is a fan assembly or unit 21 which cooperates with an engine shroud 23 to deliver cooling air around the engine block 13 and which, in accordance with the invention, provides a centrifugal fan having a. plurality of vanes 25 each with a swirl portion or configuration 27 affording increased fan efficiency. In order to permit die casting of the fan assembly 21 with swirl vane portions 27 (See FIG. 9) in accordance with the invention, the fan assembly includes two separable fan members 31 and 33, each capable of being die cast. More specifically, the fan assembly 21 includes the first or axially inner fan member 31 located adjacent to the engine block 13 and a second or axially outer fan member 33 located adjacent to and outwardly with respect to the engine block 13 of the inner fan member 31, together with interfitting means on the fan members 31 and 33 for aligning the fan members 31 and 33.

Still more particularly, the first fan member 31 (See FIGS. 2 and 3) comprises a central hub 35 which is bored at 37 for receipt of the crankshaft portion 17 and which is counterbored at 39 to receive a part of the second fan member 33. The first or inner fan member 31 also includes a base or flange 41 which extends radially outwardly of the hub 35, and a plurality of angularly spaced vane portions 43 which preferably extend from the hub 35 and flange 41 and are approximately perpendicularly to a plane perpendicular to the crankshaft axis. The vane portions 43 each include a radially extending axially outer edge 45 located remotely from the engine block 13. Each outer edge includes a slightly tapering radially outermost part 47.

In addition, as shown best in FIG. 2, when seen in a plane perpendicular to the crankshaft axis, the vane portions 43 extend, at their radially outer ends, arcuately in the direction 49 of intended rotation to adjacent the periphery of the flange 41.

Die casting of the inner or first fan member can be accomplished by using a parting line 51 for the die casting operation extending generally along the axially outer surface 53 of the flange 41 from which the vane portions 43 extend. The first or inner fan member 31 also includes appropriate draft to provide for separation from the parting surface of the die members (not shown). Other parting line arrangements could be employed.

The second or outer fan member 33 also includes (as seen best in FIGS. 7, 8 and a central hub 61 which,

when assembled with the inner fan member 31, projects into the counterbore 39. In addition, the central hub is apertured at 63 to permit passage therethrough of the crankshaft portion 17 and is counterbored at 65 as will hereinafter be referred to. Also included in the second or outer fan member 33 are a second plurality of vane portions 67 which extend radially outwardly from the central hub 61 and which correspond in angular spacing and number to the vane portions 43 of the first fan member 31. Each of the vane portions 67 includes an axially inner radially extending edge 69 located adjacent to the inner fan member 31. In order to provide the swirl configuration 27, each of the outer fan member vane portions 67 also includes an outer part 71 which extends arcuately in a plane extending parallel to the crankshaft axis and perpendicularly to a plane extending radially from and containing the crankshaft axis. Each of the outer parts 71 of the vane portions 67 of the outer fan member 33 has an axially outer margin 72. As shown in the drawings and particularly in FIG. 10, the vane portions 67 can be somewhat arcuately curved when viewed in a plane perpendicular to the crankshaft axis to conform to any curvature provided in the radially outer parts of the vane portions 43 of the inner fan member 31.

Extending from the radially outer ends of the vane portions is a generally cylindrical portion 73 which interconnects the vane portion outer ends and which, in cooperation with the central hub 61, defines an air inlet 74 for the fan assembly 21. The cylindrical portion 73 also supports a circumferential flange 75 which projects radially outwardly from adjacent the axially inner edges 69 of the vane portions 67. As can be seen best in FIGS. 8 and 10, the flange 75 includes a surface 77 which is located adjacent to the inner fan member 31 and which is slightly inclined toward the inner fan member so as to define, in the assembled fan 21 and in cooperation with the flange 41 of the inner fan member 31, a circumferentially extending outlet 79. Extending axially outwardly from the axially outer surface 81 of the flange 75 is a cylindrical portion 83 which interfits with a cylindrical groove 85 in the shroud 23 so as to provide a labyrinthe air seal.

Die casting of the outer or second fan member 33 can be accomplished by using a parting line 87 for the die casting operation extending generally along the outer margin 72 of the vane portions 67 and along the outer surface 81 of the flange 75. The second or outer fan member 33 also includes appropriate draft to provide separation from the parting line 87 of the die member (not shown). Other parting line arrangements can be employed.

In accordance with the invention, means are provided on the inner and outer fan members 31 and 33 for aligning the fan members 31 and 33. Such means also affords rotational driving of one of the fan members by the other. Various arrangements can be employed to align the fan members 31 and 33. For instance, means could be provided between the interfitting hubs 35 and 61 of the inner and outer fan members 31 and 33. In the illustrated construction, separable interfitting means are provided by utilizing the axially and radially outer parts 47 of the inner fan member vane portions 43 and by providing slots or recesses 91 in the undersurface 77 of the flange 75 of the outer fan member 33 for receipt of such outer parts 47 of the vane portions 43 of the inner fan member 31. As shown in the drawings in the illustrated construction, such slots 91 are provided by spaced arcuate projections 93 on the undersurface 77 of the flange 75 of the outer fan member 33. The location of such slots or recesses 91 insures alignment of the axial outer edges 45 of the vane portions 43 of the inner fan member 31 with the axially inner edges 69 of the vane portions 67 of the outer fan member 33 and simultaneously provides coaxial alignment between the inner and outer fan members 31 and 33.

In addition, receipt of the outer parts 47 of the vane portions 43 of the inner fan member 31 into the slots or recesses 91 in the outer fan member 33 permits rotational driving of either one of the fan members by the other fan member.

Means are provided for retaining the fan members 31 and 33 in assembled, intertitted relation to each other and for retaining the fan assembly on the crankshaft. While various arrangements could be employed, in the illustrated construction such means comprises (See FIG. 1) formation of a shoulder 95 on the crankshaft 15 limiting axially inward movement of the inner fan member 31, together with formation of threads 97 on the outermost part of the crankshaft portion 17 and employment of a nut 99 threadedly received on the crankshaft portion 17, located in the counterbore 65 of the outer fan hub 61, and operable to retain the outer fan member 33 in interfitted relation with the inner fan member 31 and to retain the assembled fan members 31 and 33 on the crankshaft 15. If desired, a washer can be employed between the nut 99 and the base of the counterbore 65 in the hub 61 of the outer fan member 33.

Means are also provided for rotatably driving the interfitted fan assembly 21 from the crankshaft 15. Various constructions could be employed. For instance, both fan members 31 and 33 could be keyed to the crankshaft 15. Alternatively, a driving member could be connected between the crankshaft and one of the fan members 31 and 33, relying on the interfitting condition of the fan members 31 and 33 to provide common fan member rotation. In the illustrated construction, such a driving member comprises a key 101 extending between the crankshaft l5 and the inner fan member 31.

While the invention has been described in connection with mounting on the crankshaft 15 of an internal combustion engine 11, it should be noted that the fan assembly 21 is adapted for mounting on any shaft. In addition, the fan assembly 21 can be employed with any type of internal combustion engine.

In assembly, the inner fan member 31 is telescopically received on the exterior crankshaft portion 17 with the key 101 in driving connection between the crankshaft 15 and inner fan member 31. The outer fan member 33 is then slipped over the crankshaft 15 and arranged relative to the inner fan member 31 so as to interfit the cooperating interfitting means on the inner and outer fan members, whereby to axially align the fan members 31 and 33 and to align the vane portions 43 and 67 of the inner and outer fan members 31 and 33. Thereafter, the nut 97 is threaded on the outer end part of the crankshaft 15 to retain the inner and outer fan members 31 and 33 in assembled relation and to retain the assembled fan 21 on the crankshaft 15.

In accordance with the method of the invention, after separate die casting of the inner and outer fan members 31 and 33, the fan members are then assembled in interfitting relation to provide the desired alignment and to provide for rotatably driving one of the fan members from the other fan member. Thereafter, the nut 99 is assembled to the crankshaft 15 to prevent disassembly of the fan members 31 and 33, one from another.

Means other than the nut 99 could be employed for retaining the fan members in assembled relation. For instance, a screw or other fastening member could be employed to fasten the hubs 61 of the outer fan mem ber 33 to the hub 35 of the inner fan member 31.

Various of the features of the invention are set forth in the following claims.

We claim:

1. An internal combustion engine comprising an engine block, a shaft journaled in said block and having a portion extending exteriorly of said block, a first unitarily cast fan member received on said shaft portion and including a base and plurality of angularly spaced vanes each extending axially of said shaft from said base and radially outwardly of the axis of said shaft and having a radially extending axially inner edge spaced from said base and including a radially outer end portion, a second unitarily cast fan member received on said shaft portion outwardly of said first fan member andincluding a circular portion having an axially inner end and an axially outer end, a circumferential flange extending radially outwardly from said axially inner end of said circular portion, and a second plurality of vanes corresponding in number and angular spacing to said vanes of said first member and extending radially inwardly from said circular portion toward the axis of said shaft and having a radially extending axially inner edge and an axially outer part extending arcuately in a plane extending parallel to the axis of said shaft and perpendicularly to a plane extending radially from and containing the axis of said shaft, separable interfitting means on said first and second fan members for aligning said axially inner edges of said first and second fan members and for rotatably driving one of said first and second fan members in response to rotation of the other of said first and second fan members, means on said shaft for retaining said first and second fan members in interfitted condition, and means on said shaft and on said other of said first and second fan members for rotatably driving said other of said first and second fan members.

2. An internal combustion engine in accordance with claim 1 wherein said second fan member flange includes a surface adjacent said first fan member and wherein said interfitting means comprises a plurality of radially extending recesses in said flange surface, and a plurality of parts of said radially outer end portions of said first member vane axially inner edges received in said plurality of recesses in said first fan member flange surface.

3. A fan assembly comprising a first unitarily cast fan member having an intended axis of rotation and including a base and plurality of angularly spaced vanes each extending axially from said base and radially outwardly of said first member rotational axis and having a radially extending axially inner edge spaced from said base and including a radially outer end portion, a second unitarily cast fan member having an intended axis of rotation and including a circular portion having an axially inner end and an axially outer end, a circumferential flange extending radially outwardly from said axially inner end of said circular portion, and a second plurality of vanes corresponding in number and angular spacing to said vanes of said first member and extending radially inwardly from said circular portion toward said second member rotational axis and having a radially extending axially inner edge and an axially outer part extending arcuately in a plane extending parallel to said second member rotational axis and perpendicularly to a plane extending radially from and containing said second member rotational axis, and interfitting means on said first and second fan members for rotat ably driving one of said first and second fan members in response to rotation of the other of said first and second fan members and for coaxially aligning said first and second fan members with said axially inner vane edges of said first and second fan members in alignment with one another and with said second fan member flange overlying said radially outer end portions of said axially inner vane edges of said first fan member, whereby to form a fan assembly inlet at the axially outer end of said second fan member circular portion and to form a fan assembly outlet at the radially outer end of said first fan member vanes between said first fan member base and said second fan member flange.

4. A fan assembly in accordance with claim 3 wherein said second fan member flange includes a surface adjacent said first fan member and wherein said interfitting means comprises a plurality of radially extending recesses in said flange surface, and a plurality of parts of said radially outer end portions of said first member vane axially inner edges received in said plurality of recesses in said first fan member flange sur- 

1. An internal combustion engine comprising an engine block, a shaft journaled in said block and having a portion extending exteriorly of said block, a first unitarily cast fan member received on said shaft portion and including a base and plurality of angularly spaced vanes each extending axially of said shaft from said base and radially outwardly of the axis of said shaft and having a radially extending axially inner edge spaced from said base and including a radially outer end portion, a second unitarily cast fan member received on said shaft portion outwardly of said first fan member and including a circular portion having an axially inner end and an axially outer end, a circumferential flange extending radially outwardly from said axially inner end of said circular portion, and a second plurality of vanes corresponding in number and angular spacing to said vanes of said first member and extending radially inwardly from said circular portion toward the axis of said shaft and having a radially extending axially inner edge and an axially outer part extending arcuately in a plane extending parallel to the axis of said shaft and perpendicularly to a plane extending radially from and containing the axis of said shaft, separable interfitting means on said first and second fan members for aligning said axially inner edges of said first and second fan members and for rotatably driving one of said first and second fan members in response to rotation of the other of said first and second fan members, means on said shaft for retaining said first and second fan members in interfitted condition, and means on said shaft and on said other of said first and second fan members for rotatably driving said other of said first and second fan members.
 2. An internal combustion engine in accordance with claim 1 wherein said second fan member flange includes a surface adjacent said first fan member and wherein said interfitting means comprises a plurality of radially extending recesses in said flange surface, and a plurality of parts of said radially outer end portions of said first member vAne axially inner edges received in said plurality of recesses in said first fan member flange surface.
 3. A fan assembly comprising a first unitarily cast fan member having an intended axis of rotation and including a base and plurality of angularly spaced vanes each extending axially from said base and radially outwardly of said first member rotational axis and having a radially extending axially inner edge spaced from said base and including a radially outer end portion, a second unitarily cast fan member having an intended axis of rotation and including a circular portion having an axially inner end and an axially outer end, a circumferential flange extending radially outwardly from said axially inner end of said circular portion, and a second plurality of vanes corresponding in number and angular spacing to said vanes of said first member and extending radially inwardly from said circular portion toward said second member rotational axis and having a radially extending axially inner edge and an axially outer part extending arcuately in a plane extending parallel to said second member rotational axis and perpendicularly to a plane extending radially from and containing said second member rotational axis, and interfitting means on said first and second fan members for rotatably driving one of said first and second fan members in response to rotation of the other of said first and second fan members and for coaxially aligning said first and second fan members with said axially inner vane edges of said first and second fan members in alignment with one another and with said second fan member flange overlying said radially outer end portions of said axially inner vane edges of said first fan member, whereby to form a fan assembly inlet at the axially outer end of said second fan member circular portion and to form a fan assembly outlet at the radially outer end of said first fan member vanes between said first fan member base and said second fan member flange.
 4. A fan assembly in accordance with claim 3 wherein said second fan member flange includes a surface adjacent said first fan member and wherein said interfitting means comprises a plurality of radially extending recesses in said flange surface, and a plurality of parts of said radially outer end portions of said first member vane axially inner edges received in said plurality of recesses in said first fan member flange surface. 